Tumbling mechanism



Mmh e, 1945.

F. C. HOFFMAN TUMBLING MECHANISM Filed Feb. 9, 1943 2 Sheets-Sheet l Vf/v TDR mfofR/@K a: HOFFMAN,

March 6,' 1945.

F. HOFFMAN TUMBLING MECHANISM Filed Feb. 9, 1945 2 sneeuw-sheet 2' /NVE/VTDR FREDER/CK C'.HFFMA/V,

H/5 ATTORNEY mechanism;

Patented Mar. 6, 1945 'roivmLING MEcnANIsM `Frederick C.Hoiman, MeridenuGonn.;assignorzto General VIMotors iCorporatiomiDetroit, -Michwa corporation. ofglelaware Application February-9, lefia'seriaiNo. 475,293

(citi- 164) f'zloiaims.

`Work. Heretofore, after emptying a tumbling barrelat the completion of a tumbling operation, the ,Work pieces had to be sorted from the tumy bling members yand from the` accumulated2 .dirt and ,scale,after which the tumbling members had te be sorted from the .dirt and scale and then returned topthe tumbling :barrel for .the next tumbling operation. These.

.sorting operations and the subsequent replace-` ment of the Atumbling members in the tumbling quenty. consume as much time as the tumbling operatiomand -this loss of time between Atumbling operations seriously retards production.

fIt is therefore anobject ci this invention'to ,provide an improved tumbling mechanism which sorts '.work ypieces from tumbling memberslatthe completion of a tumbling operation.

yAnother object is to pro-vide a tumbling barrel v -of great rsimplicity and low l cost `wherein tumv blingmembers in this barrel are separated from thewcrk pieces at the completion 4ofia tumbling operation and are retained Within the tumbling barrel when the Work pieces are emptied from ,this barrel. y I

To these ends andalso to improve generally upon devices of lthis character,theinvention con- YJsists inthe various matters rhereinafter described and claimed. In its bro-aderaspects, the invention is not necessarily limited to the snecicconstruction illustrated in the accompanyingdrawjliigure `1 is a side elevation of niyimproved tumbling barrel;

FigureZ is a 'fragmentary' cross section taken substantially along thelineaZ-2 of Figure l; y

Figure'i'is a'longit'udnal sectional vieu/taken substantially along theline ,'3-3 'of Figure Zand having parts 'broken away `to clarity the `constructiom Figure V4 .is .an end vview of the barrel closure Figure '5 is across sectional View through the .tumbling barrel and illustrating Lthe "discharge of barrel before the next tumbling operation I.fre-

.after atumbling operation.

the .tumbling eiementsintb the tumbling" chamberatthey start of a tumbling operation and yj Figure '6 is a cross sectional .view through the tumbling barrel and illustrating how 'theftumbling elements are separated from vthe Work. pieces and retained apart from the tumbling Generally stated,l I Lhave Aprovided a vrotatable tumbling barrel" il) having ,an inner Work tumbling chamber i2 abouttwhich peripherallyjex- A tends aiseries of successive G-Shapedl-o1larcllat outer chambers ifi that are arranged Ito receive tumbling elements; ,such as tumbling balls i6.

Spaced 'passages it', v extending fromfone end .of v each c:slowed chamber r4 @into the-'tumbling vchamlo-er ll2iareelach cfa szetoprovide passa-ge cnlyor the tumblingelementsl oro-nlylforthe work pieces W Whichever ,are ,smallerWhen the tumblinggelernents `are the smaller as will usually be thecaseand when the barrel is rotated one direction, the tumbling elements empty from ,the chambers jllthrough the passages I 8 linto the tumbling chamber I2 and interminglejn `ju'mbled relation with the ,work pieces W to produce a tumblingoperation, and When the barrel isrotated in the opposite direction,; th e tumbling elements Ql separate fro-inthe WorkA piecesand move'back through these passagesintofthe chambers |554 Where they remainpocketed until theneXt tumbling operation. As illustrated, each of `the chambers lil extends more than'half-Way around the tumbling chamber izsothat .the tumbling elementscannot move back into `the tumbling chamber while. the barrel 'is being rotated ,in a `direction to collect and pocket theseelementsjn the chamberslfl.l

In the illustrated embodiment, a hollow' outer Ymember ,has a generally circular outer Wal1 2,0

closedat oneend bya bottom-Wahl! havin'g an astud secured to the cover and which k operates y a 4series of Aclamping arms25 pivotally supported by cover brackets. The inner y ends .of ,these clamping arms t ,Within a groove in rthe handwheel hub, and hooked outer yendsufthese clampingarms 25 overlieand removably lclamp against Ianaunular ange 26 on the wa112 0. A sealing Washer?? may be providedbetween the cover and theange ze to prevent leakage if aliqud 1is maintained inthe barrel during av tumbling i operation.

vliti A hollowinner menlberor open endedannular shell 30 is seated atjitsinner end;in tl1e counter chamber eccentric counterbore 2 2, anda lcover 'Z3 .is'frel ,movablyV secured against the openendjof A the barrel by a handwheel 24vwhich1is threaded on bore 22, and is also longitudinally seated against an arcuate surface 3l coextensive with a portion of this counterbore and formed on a radially inward projection 32 of the Wall 26. The shell 30 has a longitudinally extending cut-out portion through which projects a keystone-shaped block 33 matingly seated against the inner surface of the wall 20 and having substantially radially disposed shell engaging faces 34 and 35. The shell 30 is also peripherally supported by a series of spaced crescent-shaped cross partitions or baffles 36 that externally seat against the inner surface of the wall 20 and which at one end abut against the block face 35 andv at the other end abut against a shoulder 31 on the wall projection 32. These baliies also separate the successive C- shaped ball receiving chambers I4. The shoulder 31 in co-operation with the wall 26, baffles 36 and shell 36 closes one end of each chamber I4 so that the tumbling elements I6`may be pocketed between tumbling operations as shown in Figure 2. The block face 34 locates against a shoulder 38 on the Wall projection 32, and the end of the block 33 adjacent to the bottom of the tumbling barrel is stepped to extend into the counterbore 22. s

An arcuate series of consecutively abutting keystone-shaped blocks 4I) matingly seat against the curved inner face of the shell 36, and two of -these blocks 4U also intert in similar keystone relation against the block 33. The blocks 33 and 40, 4which may be composed of a hard Wood or a suitable molded tough librous material such as Textolite, are respectively provided with flat inner faces 42 and 43 that co-operatively form a multi-sided tumbling chamber having angularly disposed sides which aid in turning and tumbling work pieces over each other and over the tumbling balls I6 as the tumbling barrel is rotated. The end face 34 of the block 33 projects radially inwardly beyond'the adjacent block face 43 and provides a shoulder from which the spaced passages IB angularly extend into spaced block recesses 44 each of which opens into an end of one of the chambers I4. I preferably have the bottom of each passage i8 merge with or coexten- 'sive with the adjacent face 43 so that the tumbling balls may freely feed from the tumbling chamber into the ball receiving chambers I4 when the tumbling barrel is rotated as shown in Figure 6.'

The tumbling barrel I6 is supported for rotation about a longitudinal axis by a cradle 45 supported for tiltable movement above a transverse axis by a pair of upright frames 46 and 41 so that the tumbling barrel may be tilted to a loading position A, a discharge position B and t an intermediate substantially horizontal position for a tumbling operation. A peripherally extending annular flange 48 on an intermediate portion of the tumbling barrel I8 is journalled within an annular housing 50 of the cradle; and cradle side arms, rearwardly extending from this housing, are connected by a cross arm within which is journalled a stub shaft 54 extending from the bottom of the tumbling barrel coaxially of the annular flange 48. The annular housing B has diametrically opposed bosses 55 and 56 respectively adjacent to the upright frames 46 and 41. The boss 55 is provided with a. reduced sleeve extension 51 journalled in the frame 46; and a shaft 58, secured in and laterally projecting from the boss 56 coaxially of the sleeve extension 51, is journalled in the upright frame 41. A worm wheel segment 60, fastened to the shaft 58,

meshes with a Worm 6I fastened to a worm shaft journalledin the frame 41, and a bevelled gear fastened on this worm shaft meshes with a bevelled gear 63 turned by a hand Wheel 64 for tilting the tumbling barrel to any desired position. The Worm shaft is suitably prevented from end play, and the lead of the Worm 6I is such that the worm will not be turned by the worm wheel 6I).

To provide for rotation of the tumbling barrel irrespective of the tilted position of this barrel, a

ring gear 65, secured to the annular ange 48, is

rotatably driven by a pinion 66 fastened on a shaft 61 which is journalled coaxially of the sleeve extension 51 in the boss 55 and in an arm 68 of the frame 46. Rotation is imparted to the driving pinion 66 by a reversible motor 16 belt connected to a pulley 1I that is fastened on the shaft 61.

In the operation of my invention, the uncovered tumbling barrel I0 is initially tilted to the loading position A by the hand Wheel 64, and work pieces W in sumcient numbers for a tumbling operation are placed in the tumbling chamber I2. If desired, Water or various solutions may also be placed in the barrel to aid in cleaning the work pieces and to wash out the dirt and scale from the barrel when the barrel is emptied. The cover 23 is clamped in sealing position by the hand wheel 24, and the hand wheel 64 is operated to position the barrel horizontally. The reversible motor 10 is noW operated to rotate the barrel in the direction shown in Figure 5 which causes the tumbling balls I6, previously pocketed in the various compartments of the C-shaped chamber I4,to roll in through the passages I8 into the tumbling chamber I2 where they will remain in tumbling relation with the Work pieces as long as the barrel rotation continues in this direction. After the tumbling operation, the motor 10 is reversed to rotate the barrel through a sufficient number of turns and in an opposite direction as shown in Figure 6 so that the tumbling balls I6 Will separate from the Work pieces and be directed by the shoulder 34 into the passages I8 through which they will roll into the chambers I4 where they will remain pocketed until the next tumbling rotation of the barrel. The cover 23 is next removed and the hand Wheel 64 is operated 'to tilt the barrel to the discharge position B whereupon the work pieces W will be emptied from the barrel while the tumbling balls I6 remain pocketed inthe chambers I4. The cross partitions or bafiles 36 limit the longitudinal shifting of the tumbling elements i6 so that they do not gravitate to the lower end of the barrel and force some of them back into the inner chamber. Also when the barrel is again horizontal, the elements I6 are held distributed along the length of the barrel for efficient distribution into the inner chamber in a series of streams.

I claim:

1. A rotatable tumbling barrel for tumbling Work pieces together with tumbling elements smaller than the work pieces and comprising a pair of inner and outer hollow members spaced to provide therebetween an arcuate tumbling element chamber peripherally extending more than half of the peripheral distance around said inner member, the inner member providing a tumbling chamber for both Work pieces and tumbling elements, mechanism supporting said barrel for rotation about an axis extending longitudinally through said inner member, and means providing between said chambers and located at' one peripheral end of the arcuate chamber a passage outer chamber and an inner chamber within said outer chamber, means engaging the periphery of the barrel for supporting the barrel for rotation about an axis extending through the barrel, and means providing a tumbling element passage extendingbetween the chambers and locatedv at one peripheral end of the outer chamber, said passage being too small to pass the work pieces but large enough to pass the tumbling elements into one chamber in one direction of rotation an-d to return them to the other chamber in the opposite direction of rotation.

3. A rotatable tumbling. barrel for tumbling work pieces together f with tumbling elements smaller than the Work pieces and comprising a rotatably mounted hollowouter member, a shell completely within and supported by the outer member, said shell containing a tumbling, chamber'for both the work pieces and the tumbling elements, a portion of the shell being spaced from the outer member to provide an arcuate tumbling element chamber extending about said shell, and means providing between said chambers a passage which will admit the tumbling elements and which will not admit the work pieces, the passage being located at one peripheral end of the arcuate chamber.

4. In a rotatable barrel for tumbling work pieces mixed with tumbling elements of another size, an inner shell forming an inner chamber, a substantially circular outer wall surrounding the inner shell and co-operating therewith to form,

an outer chamber extending more than half way but less than the whole peripheral distance round the inner shell, one of the chambers constituting va tumbling chamber when the barrel is rotated in one direction and the other chamber constituting a separating chamber when the barrel is rotated in the opposite direction, and the inner shell having a passage communicating with the outer chamber and of a size between that of the work pieces and the tumbling elements, the pas-V sage being located at one periplieral'end of the outer chamber. y

5. YIn a rotatable barrel for tumbling work pieces mixed with tumbling elements of another size, an inner shell forming an inner chamber, a substantially circular outer wall surrounding the inner shell and (so-operating therewith to form an outer chamber extending more than half way but less than the whole peripheral distance round the inner shell, the inner shell having a passage communicating with one peripheral end only of the outer chamber and ofv a size between that of the work pieces and the tumbling elements, and

supporting means engaging the outer wall to supe port the barrel for rotation.

6. In a rotatable barrel for tumbling work pieces mixed with tumbling elements of another size, an inner shell. forming an inner chamber, a substantially circular outer wall surrounding the inner shell and co-operating therewith to form an outer chamber, the inner shell having a series of passagesvdistributed along'its length and communicating with'the outer chamber, each passage being of a size between that of the work pieces and the tumbling elements, means to support the barrel for ti1tingmovement,'and the 'outer chamber having partitions or ballies to divide it into a series of cross compartments to limit longitudinal movement of articles contained therein when the barrel is tilted.

7. Tumbling mechanism comprising a barrel rotatable inopposite directions and having a chamber to tumble work pieces mixed. with tumbling elements of another size, the barrel having a second chamber communicating with the first chamber by a passage of a size between that of the work pieces and the tumbling elements, and one of the chambers being outside of the other and extending from the passage around `more than half of the circumference of the inner chamber but less than the whole circumference, one chamber receiving the tumbling elements alone from'the passage in one direction of rota-v tion and dischargingI them throughA the same passage into the other chamber in the opposite direction of rotation.

FREDERICK C. HOFFMAN. 

